Kamia Knuttgen

The expansion of urban areas, from a densely populated core to the periphery, has led to the conversion of cropland, pastures and forests into urban and suburban dominated systems (Frey 1984). Consequently, there is a gradient of land use types ranging in their respective domination of human influence, lessening toward the periphery. The process of urbanization results in a change of the natural environment (Dickman and Doncaster 1987), which can ultimately lead to a change in the flora and fauna composition having both positive and negative effects on the mammalian community. I studied the diversity, abundance, habitat associations, and demographic parameters of small mammal populations along an urban-rural gradient extending from the City of Spokane, Spokane County, Washington, westward, during the summer of 2000. Small mammals were live-trapped, marked, and recaptured at 9 locations representing 3 levels of human density including four habitat types: open lawn, garden/non-native ground cover, native ground cover, and tree/shrub. A total of 126 individuals (403 captures), comprising five species were trapped out of 3,713 trapnights. Species richness was lowest in the urban area and was the only area containing a non-native species, the commensal house mouse, Mus musculus. Conversely, the rural area had the highest species richness. The urban area had the lowest capture frequency and the lowest density of small mammals in contrast to the rural area, which had the highest capture frequency and density. The suburban area was intermediate in all respects. These impacts on small mammal communities reflect the role humans have, in general, on urban settings.